Define spaceship <=> operator for StrongAlias

This simplifies using standard functions that search for the
spaceship operator like std::tie.

Bug: None
Change-Id: Id7875b31858c3014b69a6eec0c5cf88ab58c7b1c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/478120
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Auto-Submit: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47880}